US2831394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catadioptric lenses
Assignee: Elastic Stop Nut Corp
•
Filing: 1952-08-22
•
Granted: 1958-04-22
•
Expires: 1972-08-22
Abstract
No abstract record available.
Inventors
- 👤 Sidney A Heenan
- 👤 Robert I Nagel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:09
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/08; F; F21; F21S; F21S43/00; F21S43/20; F21S43/26
Claims Analysis
Total Claims: 0
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-04-21 | 1961-10-21 | 1962-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-04-21 | 1965-10-21 | 1966-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-04-21 | 1969-10-21 | 1970-04-22 | $7700.00 | Window Closed / Lapsed |